The present invention relates to a mechanical pencil having a front sleeve or barrel, a cap rotatably and detachably mounted at the rear end of the front sleeve, and a lead advancing mechanism contained in the front sleeve, rotation of the cap actuating the lead advancing mechanism to advance a lead.
Such a mechanical pencil is disclosed in Japanese patent publication No. 63-84381. That mechanical pencil comprises a cam engaging means integrally connected to the rear end of a lead chuck of a lead advancing mechanism contained in a front outer sleeve and a cam sleeve connected to a rear outer sleeve. The cam engaging means is biased to engage a front end of the cam sleeve. The cam engaging mean moves to and fro in an axial direction to advance a lead in accordance with rotation of the rear outer sleeve. However, in the prior mechanical pencil, if an external shock is applied to the mechanical pencil when, for example, the mechanical pencil is dropped, the lead advancing mechanism and a front end of the front outer sleeve displace differently and any lead supported by them is broken.